A colorimetric and smartphone readable method for uracil-DNA glycosylase detection based on the target-triggered formation of G-quadruplex.

A simple, visible and smartphone readable strategy for the sensitive detection of uracil-DNA glycosylase (UDG) activity has been developed. This is based on the UDG-catalyzed removal of uracil bases, which induces the formation of a G-quadruplex-cofactor complex. The guanine-rich DNA probe can form a special G-quadruplex structure with hemin to display peroxidase activity and catalyze the H2O2-mediated oxidation of ABTS(2-) to the colored ABTS˙(-), providing a visible signal for UDG detection. The proposed sensing platform exhibits a good linear response to UDG concentrations ranging from 0.008 to 0.2 U mL(-1), with a low detection limit of 0.008 U mL(-1). Based on the theory of chromatics, we can directly read out the color value using a smartphone app to reflect the content of UDG with high resolution, providing a new vision for the portable assay strategy. Furthermore, the utility of this method for screening potential UDG inhibitors has also been demonstrated.